Eurasian Three-toed Woodpecker (Picoides tridactylus) - HBW 7, p. 494

Taxonomy:Picus tridactylus Linnaeus, 1758, Sweden. Forms a superspecies with P. dorsalis, and commonly treated as conspecific; genetic evidence, however, coupled with geographical isolation and differences in plumage, indicate that the two are probably better considered separate species. Closely related also to P. arcticus, but links with other American congeners apparently not strong. Currently accepted races designated according to coloration, but variation is clinal, birds becoming darker and larger from N to S; revision based on genetic and biogeographical grounds required. Birds from Sakhalin, described as race sakhaline.. View all taxonomy...

Taxonomy: Picus tridactylus Linnaeus, 1758, Sweden. Forms a superspecies with P. dorsalis, and commonly treated as conspecific; genetic evidence, however, coupled with geographical isolation and differences in plumage, indicate that the two are probably better considered separate species. Closely related also to P. arcticus, but links with other American congeners apparently not strong. Currently accepted races designated according to coloration, but variation is clinal, birds becoming darker and larger from N to S; revision based on genetic and biogeographical grounds required. Birds from Sakhalin, described as race sakhalinensis, appear indistinguishable from nominate; named races tianschanicus (Tien Shan), kurodai (Korea) and inouyei (EC Hokkaido) barely differ from European alpinus, thus regarded as better merged with that taxon. Five subspecies recognized.